file

file

In hardware and metalworking, bar- or rod-shaped tool of hardened steel with many small cutting edges raised on its surfaces. Files are used for smoothing or forming objects, especially of metal. A file's cutting or abrading action results from rubbing it, usually by hand, against the workpiece. The single-cut file has rows of parallel teeth cut diagonally across the working surfaces. The double-cut file has rows of teeth crossing each other. Rasp teeth are disconnected and round on top; rasp files are usually very coarse and are used primarily on wood and soft materials.

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A collection of bytes stored as an individual entity. All data on disk is stored as a file with an assigned file name that is unique within the folder (directory) it resides in.

To the computer, a file is nothing more than a string of bytes. The structure of a file is known to the software that manipulates it. For example, database files are made up of a series of records. Word processing files contain a continuous flow of text.

Except for ASCII text files, which contain only raw text, other files have proprietary structures. Formatting and other types of information are contained in headers or interspersed throughout the file. Following are the major file types. See file association.

   Type                 Contents
   data file (table)    data records
   document             text
   spreadsheet          rows and columns of cells
   image                rows and columns of bits
   drawing              list of vectors
   audio                digitized sound waves
   MIDI                 MIDI instructions
   video                digital video frames
   Web page             text
   batch file           text
   source program       text
   executable program   machine language

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(file system)

file - An element of data storage in a file system. The history of computing is rich in varied kinds of files and file systems, whether ornate like the Macintosh file system or deficient like many simple pre-1980s file systems that didn't have directories. However, a typical file has these characteristics: * It is a single sequence of bytes (but consider Macintosh resource forks). * It has a finite length, unlike, e.g., a Unix device. * It is stored in a non-volatile storage medium (but see ramdrive). * It exists (nominally) in a directory. * It has a name that it can be referred to by in file operations, possibly in combination with its path. Additionally, a file system may support other file attributes, such as permissions; timestamps for creation, last modification, and last access and revision numbers (a` la VMS). Compare: document.